The present invention relates generally to high-profile bulked multi-layer plastics material structures in which at least one layer is in a non-planar configuration. A high-profile structure has a thickness considerably greater than that of a bulked textile fabric. The thickness should in general be such as to be capable of restraining the movement of soil or gravel filling the reentrants in a profiled face of the structure when the structure is at a steep angle.
In a flexible form, such structures can be used for soil retention. The structure is placed on e.g. an embankment and may be filled with e.g. soil and grass seed. The grass seed grows and its roots entwine the structure, preventing gross erosion by heavy rainfall or the wave action of a river or sea. The structure itself can be pegged down to provide firm retention, at least in the initial stages of root growth.
A more rigid structure can for instance be used as a spacer for soil drainage, particularly when the compression resistance need not be too high. One or both faces of the structure would be provided with a layer of geofilter to prevent the structure filling with soil or silt and to maintain gaps within the structure through which water can drain.
It is desirable to be able to form high-profile structures which are dimensionally stable and fairly regular, in a quick and simple manner in a modern manufacturing plant. It is also desirable to develop a structure which does not have large through-channels which could lead to scouring in soil retention.